Portable telephone transmitter and receiver or testing instrument.



H. P. THOMA, JR. & G. E. MoGREW.'.

ONE TRANSMITTER AND RECEIVER 0R TESTING INSTRUMENT;

APPLICATION FILED DEO.14, 1907;

PORTABLE TELEPH 946,41 0, Patented Jan. 11,-1910.

Witness e81 UNITED STATES PATENT onnion.

HENRY F. TI-IOMA, JR., AND CLIFFORD E. MCGREW, OF CHICAGO, ILLINOIS, ASSIGNORS OE ONE-HALF TO HENRY F. THOMA, ONE-FOURTH TO HENRY F. THOMA, JR., AND ONE-FOURTH TO CLIFFORD E. MQGREW, ALL OF CHICAGO, ILLINOIS.

PORTABLE TELEPHONE TRANSMITTER AND RECEIVER 0R TESTING INSTRUMENT.

Application filed December Specification of Letters Patent.

Patented Jan. 11, 1910.

14, 1907. Serial No. 406,541.

To all whom it may concern:

Be 1t known that we, HENRY F. Trronn, Jr., and CLIFFORD E. MoGREw, both citlzens of the United States, residing in Chicago,

in the county of Cook and State of Illinois,

have invented certain new and useful Improvements in Portable Telephone Transmitters and Receivers or Testing Instruments, of which the following is a specification.

This invention relates to that class of telephone transmitters and receivers which are testing telephone lines, communicating with the central station from any desired point on the line or wire, sending or receiving messages from points where there is no regular or permanent stationary instrument, or to be carried from place to place and frequently attached and detached as required in use in connection with construction or repair work of telephone lines, or for other purposes.

The principal object of the invention is to provide a simple economical, light, portable and durable telephone instrument or transmitter and receiver.

Other and further objects of the invention will appear from an examination of the drawings and the following description and claims.

In the art to which this invention relates principally of metal or having the connectmg arm between the transmltter and re ceiver made of metal are undesirably heavy and cumbersome, and that the wires and their connections used in an instrument having such a metallic arm, or other unnecessarily heavy metallic parts, require insulation, and render the instrument more complicated, more cumbersome and more liable to convey an electric shock to the operator to his injury, than is desirable.

One of the principal objects of the invention, therefore, is to provide a telephone transmitter and receiver or testing instrument which is adapted to overcome these objections and disadvantages.

The invention consists in the features, combinations and details of construction hereinafter described and claimed.

In the accompanying drawings Figure l i is a plan view of an instrument or headset constructed in accordance with my im- Q provements; Fig. 2, a central sectional elevation of the same; and Fig. 3, a bottom 1 view, with the filling for the bottom slot l omitted, to show the wire connect-ions; and Fig. 4, a bottom view of the connecting arm l and guard, as it. appears when the bottom 1 slot is filled withins'ulating material to cover and protect the wires and their connections. In constructing a portable transmitter and E receiver in accordance with our improvements, we provide a receiver 0, having a casing formed of insulating material and consisting of a main body portion 6 and a cap 0, removably secured to said main body portion of the casing. A transmitter (Z is provided, having a casing formed of what is known as vulcanized fiber, and this transmitter casing consists of a main body portion c and a cap or cover f removably secured to the main body portion of the casing by means of screws g. The cap is provided with a series of perforations h which com- 1 municate with the inner chamber z" formed by the cap and cover or casing. A connecting arm and guard j is also formed of nonconducting material or insulation known as vulcanized fiber and forms a support and means for rigidly connecting the transmitter and receiver. It also forms a guard for the connecting wires 70 and Z which are laid in a slot at in the under side of the arm, and extending longitudinally thereof from a point beneath the transmitter to the receiver, or from end to end of the arm. This slot is filled with insulating material in the form of a paste which is allowed to harden, and which covers and protects the wires. Screws or posts a and 0 are mounted in one end portion of this arm of insulating material and extend into the transmitter casing, with their heads or bottom ends connected with the 1 wires Z and 70 respectively as shown. Screws or posts 79 and q are mounted in the opposite end portion of the arm and extend into the receiver casing, their bottom ends or heads being connected with the wires 70 and Z respectively, as shown. The screws n, 0, p and g are all of metal and properly threaded, 1 and thus form the means for securing the transmitter and receiver casings to the arm and guard, and also form, with the wires k and Z a metallic circuit for electrically connecting the transmitter and receiver with each other and with the telephone line.

The transmitter is provided with a mc tallic diaphragm r having a carbon plate .9

secured to its inner or under side by means bon plate is partially filled with carbon dust E or filings 2 and the diaphragm is connected 1 with the screw a by a wire which extends through a slot 2 in the main body portion of the transmitter casing. It will be seen that the transmitter casing and the connecting arm or guard j are formed of fiber, commonly known as vulcanized fiber, throughout. In other words, they are formed entirely of insulating material or a nonconductor of electricity in the form of compressed fiber which enables metallic guards and strengthening pieces or connecting arms to be entirely dispensed with, and also enables the electrical connections to be readily assembled and maintained in good working order and without the use of any metallic parts except those actually forming a part of the electric circuit.

A wire 3 connects the screws o and 0, and with the wire 7: and screw 7) forms the electrical connections between the carbon plate 1.4 and the receiver. The receiver casing is also formed preferably of fiber, so that the entire instrument, with the exception of the metallie and carbon electrical connections, is formed of insulating material or an electrical nonconductor which is sufficiently strong to withstand the strains to which it is subjected in use, and which is not only an insulator but forms a supporting frame and protecting casing which incloses and protects all of the metallic and electrically operated and electric circuit forming parts. strument is thus adapted to protect the operator to the greatest possible extent from electric shocks, and is both light and durable.

The electrical. connections in the receiver may be of any ordinary and well known form, and it is therefore not deemed necessary or desirable to describe them in detail herein, except to show that they are all inclosed, so that, with the transmitter and connecting arm or guard constructed as dc-;-

The ini scribed, the outer portion or casing of the 1 entire instrument IS a nonconductor of elecprovided with an insulated wire 7 which is connected with the main line wire in any ordinary manner, as by means of a metallic clip or clasp, not shown. The screw p, which is connected with the transmitter by means P of the wire Z: is connected with the coil 5 which encircles the magnet or core 10. and the coil is connected with a post identical with the post a and which is in contact with a plug or pin 8. said pin being preferably insulated and connected with the main or line wire by means of a wire 9 and in the same manner as wire T. already described.

Ye claim:

1. In a device of the class described, the comhimition of a transmitter casing, a receiver casing. a connecting arm connecting and forming a support for the transmitter and receiver casings, said transmitter casing and arm being formed of insulating compressed fiber, metallic transmitter and receiver mechanism mounted in the transmitter and receiver casings respectively, wires inside of the connecting arm, connecting said transmitter and receiver mechanism and embraced within and forming part of an elec' tric circuit. and metallic screws connecting the transmitter casing with said arm, said screws being in contact: with said wires and embraced within and forming part of the electric circuit, said arm and transn'iitter casing forming an insulating covering for said screws and wires.

2. In a device of the class described, the combination of a transmitter casing, a receiver casing, a connecting arm connecting and forming a support for the transmitter and receiver casings, said transmitter casing and arm being formed entirely of insulating con'ipressed fiber, transmitter and receiver mechanism comprising metallic parts mounted in said casings, metallic wires in said arm. metallic screws connecting the transmitter asing with said arm, said screws forn'iing a connection between said wires and the metallic parts of the transmitter mechanism which is inside of the transmitter casing, and being embraced within and forming a part of the electric circuit, and metallic screws connecting the receiver casing with said arm and connecting said wires with the receiver mechanism which is inside of the receiver casing and embraced within and forming part of the electric circuit, all of said metallic parts, including said screws and wires being entirely inclosed by said casings and arm of insulating material.

3. In a device of the class described, the combination of a transmitter casing, a receiver casing. a connecting arm connecting and forming a support for the transmitter and receiver casings, transmitter and receiver mechanism comprising metallic parts in said transmitter and receiver casings respectively, and provided with wires and metallic screws mounted in said arm and forming a connection between the metallic parts of the transmitter and receiver mechanism and embraced Within an electric circuit, said transmitter casing and arm being formed entirely of insulating compressed fiber, and said casings and arm forming an insulating covering which incloses all of said metallic parts.

a. In a device of the class described, the combination of transmitter and receiver mechanism comprising connected metallic parts forming an electric circuit, a transmitter casing formed of insulating compressed fiber, a receiver casing formed of insulating material, a connecting arm formed of insulating compressed fiber and forming a connection between and support for the transmitter casing and receiver casing, all of said metallic parts being embraced Within and forming a part of the electric circuit, metallic screws embraced Within and forming part of the electric circuit and adapted to connect the casings with the arm, said casings and arm forming an insulating covering Which incloses all of said metallic parts, and means for connecting the device with a telephone Wire.

HENRY F. THOMA, JR. CLIFFORD E. MOGREW.

Witnesses:

HARRY IRWIN CRoMER, N ELLIE E. GEORGE. 

